The twenty-first century has witnessed an exponential growth in the amount of digitized information that people and companies generate and store. This information is composed of electronic data that is typically stored on magnetic surfaces such as disks, which contain small regions that are sub-micrometer in size and are capable of storing individual binary pieces of information.
Because of the large amount of data that many entities generate, the data storage industry has turned to network-based storage systems. These types of storage systems may include at least one storage server that forms or is part of a processing system that is configured to store and to retrieve data on behalf of one or more entities. The data may be stored and retrieved as storage objects, such as blocks and/or files.
One system that is used for storage is a Network Attached Storage (NAS) system. In the context of NAS, a storage server operates on behalf of one or more clients to store and to manage file-level access to data. The files may be stored in a storage system that includes one or more arrays of mass storage devices, such as magnetic or optical disks or tapes. Additionally, this data storage scheme may employ Redundant Array of Independent Disks (RAID) technology.
Another system that is used for storage is a Storage Area Network (SAN). In a SAN system, typically a storage server provides clients with block-level access to stored data, rather than file-level access to it. However, some storage servers are capable of providing clients with both file-level access and block-level access.
Regardless of whether one uses NAS or SAN, the storage of electronic data presents two primary challenges: (1) how to protect against loss of data; and (2) how to reduce the costs of storing data. Unfortunately, these two challenges push a person in desire of storing data in different directions.
Historically, in order to protect against a loss of data, persons made wholesale back-up copies of their files. However, this proved to be cumbersome. In order to render the process of storing and backing-up data more efficient, RAID technologies were developed. Unfortunately, these technologies typically provide localized data protection that primarily protects against corruption of data, not destruction of recording media. Thus, depending on the extent of physical harm that may befall the physical environment of a recording medium, the use of RAID technologies may or may not be effective because the same physical harm may befall the back-up copy or copies.
Additionally or alternatively, one can make use of data replication technology that calls for the transmission of digital information over a network to a remote site. However, there is a physical distance constraint that is a function of the distance between sites and that limits the effectiveness of this strategy. For example, limitations are imposed by the speed of light, the rate of data ingestion, and the rate of daily data change. Moreover, there are economic costs associated with making an additional copy and storing an additional copy of data, and there is a devotion of time that is necessary when one makes copies. Still further, there is always a desire to introduce protection against improper access to data.
Therefore, there is a need for new methods and systems for economically storing and retrieving data.